Some games from the 90s that supported both VGA and SVGA graphics mode (or were released as DOS VGA games but then ported to another platform with high-resolution options like Mac) have a separate set of menu graphics and fonts for high resolutions. The hi-res fonts are not a polished double-sized version of VGA fonts but take into account aspect correction of the VGA mode screen. A good example of this is Descent II.

From what I read here, the current version of ECWolf does not perform aspect correction on the menu screens and the Read This! pages (at lower resolutions) precisely for the reason that nearest-neighbour scaling would result in a very distorted, uneven shape of the letters. I believe that the only proper solution to this is to use a high-resolution font that accounts for aspect correction, just like authentic games from the 90s would do.

With this in mind I have thrown together a mockup of the Wolf3D main menu:

This is the result of manual editing of a DOS version screenshot that has been resized to 640x480 using nearest neighbour scaling.

Initially I wanted to try polishing a high-resolution, aspect-corrected version of the "Options" title as well, but this Gothic styled font would need to be completely redrawn to look good in high resolution, which is something beyond my ability. However I checked out the Mac version of the game and it doesn't scale up or correct the "Get Psyched!" message during level loading (screenshot), which actually is good enough on its own. In fact, it might very well be the case that this font was not created with aspect correction in mind.

The pistol could use some re-drawing by an artist as well, but I just smoothed the edges for now.

Do you think this could be implemented in ECWolf as an optional mod at least?

When talking about aspect correction, there are two things to keep in mind. First, when games get up scaled officially, it's not uncommon at all for aspect ratio correction to be left out of the equation. Secondly, id has been known to mix aspect correct and incorrect resources based on the size of the resource. (For example IIRC in Doom the power up spheres are circles in 1:1, but other graphics like the title screen, player sprites, mug shot, etc are obviously aspect corrected.) I guess what I'm trying to say is it's not an exact science and artistic liberties can be taken here since it was often done back in the day.

Should be possible to do what you want in ECWolf the only catch is that the font is going to be annoying. Both since ZDoom's font system which ECWolf uses is not designed for 1bpp fonts (easily worked around but wasting a non-printable character to define contrast), but also because the single lump font formats don't support scaling. You will need to make the font such that each character is a separate image and then scale them either by defining each character in TEXTURES or by having the low resolution version present and using the hires directory.